Factory world, Koburg Combine
Mimiis is a heavily industrialized world, mainly because it's not much use for anything else. There is a government, but real power rests in the hands of the Koburg Combine, a sector-sized corporation with a tough reputation in business.
40% of the mainworld's surface is occupied by the huge, largely automated factories owned by Koburg, and which produce ground cars, building parts, civilian air/rafts and boats.
The mainworld of the Mimiis system is a dark, cold place, bereft of vegetation or much sign of human occupation. The vast sprawl of the automated factories run by the Koburg dwarfs the downport, which is itself almost entirely cargo facility.
The majority of the population - and indeed the bulk of the iceberg-like factories - is housed underground. The subterranean cities are linked by a rather antiquated MagLev monorail, and in fact the Koburg discourages citizen travel between cities. Materials from and products to the downport are transported on a much superior underground GravLev, not accessible to passengers.
The capital, Transom, is located adjacent to Sanano Down Starport, and is the site of Koburg's main HQ. The other two major cities are Deeperdown and Versquel.
There's no atmosphere and no native life.
The average interstellar traveler coming to Mimiis will generally take the MagLev from the starport to Transom, stay in a hotel there, conduct his business, and leave the way he came. Travel to the other cities is not encouraged for offworlders either.